Smoking composition containing alumina and smoking unit containing same



United States Patent 3,076,728 SMOKENG CGMPGHTIU'N CGNTAINING ALUMlNAAND SMQKING UNIT CONTAINHNG SAME Charles G. Albert, Basking Ridge,N.Zl., assigner to Minerals & @hemicals lhilipp Corporation, acorporation or Maryland No Drawing. Filed Feb. 12, 1960, Ser. No. 8,2412 filaims. (Cl. 131-17) there exists strong clinical, statistical andpathological evidence that certain constituents of tobacco smokecondensate (or tars as such condensate is usually termed) arepotentially carcinogenic when deposited on human tissue. Secondly, asidefrom their alleged pathological ,efiect, it appears that certainconstituents of tars are responsible for the sharp irritating tasteimparted to smoke from a cigarette or the like. Furthermore, tarsproduce disfiguring coloration of the teeth of many smokers, and if onlyfor this reason, the lowering of total tars yielded during smoking ishighly desirable.

Accordingly, it is a principal object of the instant invention toprovide a tobacco composition which incorporates a novel aluminousadditive which functions during the pyrolysis of the tobacco to reducesubstantially the quantity of tars in the smoke efiiuent from saidtobacco.

Another object of the invention is the provision of a compositionincluding tobacco mixed with an innoxious aluminous additive capable atthe elevated temperatures encountered in smoking tobacco ofsubstantially lowering the yield of tars in the mainstream smoke oftobacco.

Other objects will be apparent from the description of the inventionwhich follows.

I have discovered that when a small amount of a unique form of alumina,hereafter described, is mixed directly with smoking tobacco, thequantity of tar normally produced by a given weight of tobacco isreduced appreciably.

Stated briefly, to acco co positio .s of the resent invention compriseaTunifor mixtur of toba co with a small 'quantity of finely dvidedicroporou alumina which is produced by therm ldecomposition of aluminumacetate. When such a tobacco composition is smoked, the amount of tarpresent in the mainstream smoke, that is, the smoke which passes throughthe mouth end of the smoking article containing the tobacco mixture, isreduced substantially from that produced by the same weight of tobaccobut in the absence of the alumina. The smoke from such mixture is verymild and is considered very pleasant by smokers. The alumina I employ isinnoxious and has no harmful effect on the smoker, even if it passesinto the smokers mouth.

It has been found, contrary to expectations, that the various aluminasproduced by thermal decomposition of aluminum salts do not possess as aclass the, physical properties of the alumina obtained by ignition ofaluminum him which, after grinding,

3,7b,?28 Patented Feb. 5, lQbS ice acetate and do not produce the sametar reduction when mixed with smoking tobacco. For example, thermaldecomposition of aluminum tartrate results in an alumina which haslittle effect on the tar content of smoking tobacco when mixedtherewith. Aluminas produced by thermal decomposition of aluminum saltsother than aluminum acetate are outside the scope of my invention.

I am Well aware that it has been suggested in the prior art to dispersein smoking tobacco various colloidal aluminas and hydrates of alumina aswell as so-called light alumina hydrate in order to sorb variousundesirable components of tobacco smoke. Activated bauxite, a form ofamorphous alumina, has been suggested as a carrier for moisture ormenthol. The specific form of alumina I employ differs profoundly in itsphysical and/or chemical characteristics from these as well as otheraluminous materials suggested as tobacco additives. It has been foundthat many aluminas such as, for example, alpha-alumina trihydrate(bauxite) and alumina produced from alpha-alumina trihydrate by thermalactivation, do not produce the desired tar reduction when mixed withtobacco. In fact, the latter form of alumina actually increases theamount of tar in the smoke produced by cigarette tobacco when it isuniformly mixed with the tobacco in the amount of 5% or 10% by weight.It is not presently understood why the alumina produced by thermaldecomposition of aluminum acetate should have an effect on thecombustion products of tobacco mixed therewith which is so differentfrom the effect of alumina produced by thermal decomposition of asimilar aluminum salt or from some highly sorptive alumina andaluminosilicates as, for example, the alumina produced by activation ofalphaalumina trihydrate.

The starting material I employ in the preparation of the novel aiuminoustobacco additive substance is aluminum acetate or any of the basicaluminum acetates. For reasonsof economy, I prefer to'use the basicaluminum acetates, especially the basic diacetate, AMOH) (Cg-1 0 Inpreparing the novel form of alumina, aluminum acetate is ignited tooxidize completely the hydrogen and carbonaceous matter into volatilecombustion products, leaving a white essentially pure anhydrous aluminaresconsists of white, iiuffy, microscopic particles. These particlesappear to be poorly ordered when examined under X-rays.

The alumina product has a B.E.T. surface area of about to square metersper gram. BET. surface area refers to surface area of a product asdetermined by a nitrogen adsorption method described by S. Brunauer, P.H. Emmett, and E. Teller in their article entitled Adsorption of Gasesin Multi-lldolecular Layers, on page 309 of Journal of the AmericanChemical Society,

'vol. 60, February 1938, using the molecular size data of H. K.Livingston presented in his article entitled Cross- Sectional Areas ofMolecules Adsorbed on Solid Surfaces, on page 569, Journal of theAmerican Chemical Society, vol. 66, April 1944.

In igniting the basic aluminum acetate, a charred in termediate productis produced and ignition is carried out at a temperature and for a timesufficient to oxidize completely the hydrogen and carbonaceous matter.Calcining aluminum acetate in the presence of air (or other suitableform of available oxygen) at 1200 F. to 1500 F. for a time sufficient tooxidize completely oxidizable matter in the starting material isrecommended. The calcination time, which will vary with the furnaceemployed and the quantity of material being processed, will usually befor 1 to 24 hours. A suggested method of obtaining the desired aluminais to calcine basic aluminum diacetate for 2 hours in a mufile furnaceheld at 1400 F. After calcination, the product is ground to the desiredparticle size, usually 100% by weight finer than 325 mesh.

The tobacco I employ is conventional leaf tobacco of the type used incigars, cigarettes or pipes. It is reasonable to expect thatreconstituted tobacco or mixtures of tobacco leaf and reconstitutedtobacco may be used.

In putting my invention into practice, the alumina powder obtained bydecomposing aluminum acetate is uniformly mixed with tobacco leaf inamount of about 1% to 20%, and preferably to 15%, based on the weight ofthe tobacco. Any method of uniformly dispersing the alumina powder onthe tobacco particles may I e employed and, inasmuch as the aluminaparticles are extremely small, they will adhere well to the tobaccowithout use of an adhesive substance. The additive may be applied bydusting the dry material on the tobacco, by spraying a dispersion of theadditive in a liquid or gaseous carrier or by other means which willreadily suggest themselves to those skilled in the art. Preferably, thetobaco to which the solid alumina additive is applied is in a formsuitable for direct use in the cigarette or other smoking article forwhich it is intended, namely, tobacco which has been aged, shredded,humected and treated with flavoring agents and such othertobaccotreating materials as may be desired. If desired, an adhesivesubstance, inorganic or organic, may be employed to secure the finelydivided alumina to the tobacco.

A filter tip integral with the column ofthe mixture of alumina andtobacco shreds may, if desired, form the month end of a cigarette of myinvention. The filter tip may contain fine fibers or it may contain anymicroporous material which is used in a filter tip for a cigarette. Thefilter tip in a cigarette of the present invention will serve aplurality of important functions. It will supplement the tar reductionrealized through the use of the alumina and it will prevent finelydivided alumina particles from passing into the smokers mouth.

The following examples are given to illustrate more fully my invention.

Tests were conducted to demonstrate that the total quantity of tarpassing into the mainstream of the smoke from a given weight ofcigarette tobacco is significantly reduced by mixing the tobacco withalumina which is produced by ignition of basic aluminum acetate. SimilarThe calcined material was ground to 100% minus 325 mesh. The product wasa white, fluffy powder having a BET. surface area of 117 square metersper gram and consisting of a substantially pure form of alumina.

5 A blend of Turkish and domestic cigarette tobacco supplied under thetrade name Bugler was used in all of the smoking experiments.

Experimental cigarettes were prepared by uniformly dry mixing 100 partsby weight of the tobacco shreds with parts by weight of the aluminapowder prepared from aluminum acetate and packing about 0.99 gram ofthis mixture (containing about 0.90 gram of tobacco) into a cigarettepaper wrapper. The approximate weight of the cigarette wrapper was 60milligrams. Control cigarettes containing about 0.90 gram of the Buglertobacco per cigarette were prepared. Also made up were cigarettescontaining 100 parts by weight of tobacco and 10 parts by weight ofalumina produced by calcining aluminum tartrate at 1400 F. for 2 hours.All cigarettes were conditioned at 24 C. and 58% RH. before smoking.

All cigarettes were mechanically smoked by the method described indetail in Industrial and Engineering Chemistry, vol. 28, No. 7, in anarticle entitled Nature of Cigarette SmokeTechnique of ExperimentalSmoldng, J. A. Bradford et al., pp. 836-839 (1936).

Cigarettes were smoked individually employing a constant puff of about 2seconds duration once each minute and with suflicient puffs to leave abutt of about 22 mm. The smoke from 5 cigarettes of a given compositionwas collected in a glass-wool trap packed to give about 40 cm. waterpressure drop at a flow rate of 1050 cc. of air per minute. This trapwas shown to collect at least 95% of the nonvolatile components of thesmoke. The trap was evacuated for 20 minutes and weighed. The weightincrease divided by 5 was reported as the milligram of tars percigarette.

The results reported in the accompanying table represent the average ofthree determinations, each determination representing the result ofsmoking 5 cigarettes of the reported composition.

These results show that the alumina produced by thermal decomposition ofaluminum acetate was highly effective in reducing cigarette tars,whereas the alumina similarly produced by thermal decomposition ofaluminum tartrate had a much smaller effect on total tars.

Similar smoking tests were conducted using alphaalumina trihydrate inthe amounts of 5% and 10% of the tobacco weight and activated bauxite(chiefly an amorphous pure alumina) in the amount of 5% of the tobaccoweight. It was found that the activated bauxite reduced total tars byonly 2% and that 5% and 10% of alphaalumina trihydrate actuallyincreased the tars by 11% and 2%, respectively.

The Effect of Mixing FinelyDivided Aluminas Produced by Ignition ofOrganic Aluminum Salts With Cigarette T obrzcco on the Total Tar Contentof Cigarette Smoke Av. Av. Wt. Pressure Av. Butt Av.Tars PercentComposition of Cigarette oi Ciga- Drop Av. No. Length, Per Cigaar rette,gm. During oi Puffs min. rette, mg. Reduction Smoking, cm. 1120 ControlCigarette (no alumina) 0. 9464 4. 5 9. 4 21. 9 34. 9 CigaretteContaining 10% Alumina from Ignited Basie Aluminum Acetate 1. 0222 5. 48. 5 22. 5 27. 5 21. 5 Cigarette Containing 10% Alumina from IgnitedAluminum Tartrate 1. 0237 5. 3 9. 6 20. 9 32. 7 6. 3

1 Based on weight of tobacco.

2 Basic aluminum acetate ignited at 1400 F.I2 hr. 3 Aluminum tartrateignited M1400 F./2 hr tests were conducted to show the behavior of otheraluminas with the same tobacco.

Basic aluminum diacetate, Al(OH) (C H O was placed in a'muffle furnaceheld at 1400 F. for 2 hours.

I claim:

1. A smoking mixture comprising tobacco shreds hav-- ing uniformilymixed therewith a small quantity of the finely divided high surface areaalumina produced by thermal decomposition of a basic aluminum acetate inan oxidizing atmosphere at a temperature and for a time suflicient tooxidize completely hydrogen and carbonaceous matter therein intovolatile combustion products.

2. A cigarette containing the smoking mixture of 5 claim 1.

References Cited in the file of this patent UNITED STATES PATENTS2,007,407 Sadtler July 9,1935

6 Allen Apr. 19, 1938 Patrick Oct. 7, 1941 Haden Apr. 19, 1960 HadenJune 21, 1960 FOREIGN PATENTS Great Britain 1905

1. A SMOKING MIXTURE COMPRISING TOBACCO SHREDS HAVING UNIFORMILY MIXEDTHEREWITH A SMALL QUANTITY OF THE FINELY DIVIDED HIGH SURFACE AREAALUMINA PRODUCED BY THERMAL DECOMPOSITION OF A BASIC ALUMINUM ACETATE INAN OXIDIZING ATMOSPHERE AT A TEMPERATURE AND FOR A TIME SUFFICIENT TOOXIDIZE COMPLETELY HYDROGEN AND CARBONACEOUS MATTER THEREIN INTOVOLATILE COMBUSTION PRODUCTS.